Shift control apparatus for vehicular automatic transmission and method thereof

ABSTRACT

An automatic shift control is executed in an automatic transmission with 5 shift speeds of range hold type in the highest gear stage of a shift range at the manual shift mode. Upon selection of a shift mode from the automatic shift mode to the manual shift mode, the shift range at the manual shift mode is selected in accordance with the vehicle speed detected at the automatic shift mode. If the vehicle speed is in the low-speed range, the shift range  3  is selected. If the vehicle speed is in the medium-speed range, the shift range  4  is selected. If the vehicle speed is in the high-speed range, the shift range  5  is selected.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of application Ser. No. 10/449,114,filed Jun. 2, 2003, now U.S. Pat. No. 7,001,307 the entire comments ofwhich are incorporated herein by reference.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Applications No. 2002-230405 and2002-171273 filed on Aug. 7, 2002 and Jun. 12, 2002, including thespecification, drawings and abstract are incorporated herein byreference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a shift control apparatus for a vehicularautomatic transmission and a shift control method, which allow a vehicleoperator to perform manual selection of gear stages.

2. Description of Related Art

When the gear stage is in a drive (D) position operated by the vehicleoperator using the shift device, a shift control apparatus of theautomatic transmission for the vehicle serves to select an appropriategear stage in accordance with the current operating state of thevehicle. Then a hydraulic control portion of the automatic transmissionis controlled such that the gear is automatically changed to theselected stage.

The operating state of the vehicle is determined by the shift controlapparatus based on a throttle opening and a vehicle speed, for example,and the gear stage is selected so as to provide the fuel efficiency andpower most suitable for the operating state.

There has been introduced an automatic transmission that allows thevehicle operator to manually change gear stages in order to realize notonly the aforementioned function but also the vehicle operation thatreflects the intention of the vehicle operator.

In the shift control apparatus in the automatic transmission for avehicle disclosed in JP-A-6-221417, for example, the shift deviceincludes ranges D, and B that can be selected from the range D by manualoperation of the vehicle operator. The shift device further includes anupshifting position and a downshifting position that can be selected inthe range B. An electronic control unit that serves to perform shiftcontrol of the automatic transmission becomes an automatic shifting modein the range D such that the appropriate gear stage can be automaticallyselected in accordance with the operating state of the vehicle. Uponchange in the shift range from the range D to B, the electronic controlunit sets a manual transmission mode where the gear stage is downshiftedso as to be lower than the gear stage that has been selected in therange D. When the vehicle operator performs downshifting in the range B,the electronic control unit downshifts the gear to be one stage lower.Meanwhile, when the vehicle operator performs upshifting in the range B,the electronic control unit upshifts the gear to be one stage higher.

In order to obtain the engine braking force higher than that obtained inthe gear stage that has been set during running at the automatictransmission mode, the vehicle operator changes the shift range from therange D to B using the shift lever so as to perform downshifting to thegear as being one stage lower. In order to obtain higher accelerationtorque or the torque for running uphill, the aforementioned change inthe shift range is performed to establish the gear to be one stagelower.

In the state where the automatic transmission includes 5 shift speeds,when the vehicle operator releases the accelerator pedal during runningin the 3rd speed at the automatic transmission mode, upshifting from the3rd to the 5th speed is performed by the electronic control unit inresponse to the operating state of the vehicle, that is, the state ofthe throttle valve which has been fully closed.

When the vehicle operator changes the shift range from the range D to Bfor downshifting to apply further higher engine braking force, thedownshifting is performed from the 5th to the 4th speed. Then furtherdownshifting in the range B changes the gear stage from the 4th to the3rd speed.

In the above case, the engine braking force required by the vehicleoperator cannot be obtained because the gear stage has been originallyset in the 3rd speed at the automatic transmission mode. The vehicleoperator, therefore, has to perform further downshifting from the 3rd tothe 2nd speed.

Depending on the operating state of the vehicle, the vehicle operatorhas to perform downshifting twice so as to obtain the required enginebraking force. Even in the state where the 5th speed is set in the rangeB at the manual transmission mode and the vehicle operator releases theaccelerator pedal, the gear is held in the 5th speed by the electroniccontrol unit.

If the vehicle is running downhill in the aforementioned state, thevehicle will be accelerated without depressing the accelerator pedal.When the vehicle operator performs downshifting once for the purpose ofapplying the higher engine braking force just before entering to a sharpcurve while running downhill, the gear stage is shifted from the 5th tothe 4th speed.

As the engine braking force obtained in the 4th speed is insufficient inthe above case, the vehicle operator has to perform further downshiftingonce to the 3rd speed.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a shift control apparatusfor a vehicular automatic transmission in which a shift mode is selectedbetween an automatic transmission mode for automatically setting a gearstage and a manual transmission mode for manually setting the gear stageby a manual operation of the vehicle operator such that the requiredgear stage can be established by the reduced frequency of the manualshifting operation.

It is further an object of the invention to provide a shift controlapparatus for a vehicular automatic transmission which allowsestablishment of the required gear stage by the reduced frequency of themanual shifting operation after changing the shift mode from theautomatic mode to the manual mode.

It is still further an object of the invention to provide a shiftcontrol apparatus for a vehicular automatic transmission which allowsestablishment of the required gear stage by the reduced frequency of themanual shifting operation at the manual shifting mode.

In an embodiment of the invention, a shift control apparatus for avehicular automatic transmission sets an automatic shift mode in which agear stage is established based on a first vehicle operation informationused for selecting a gear stage of the automatic transmission, and amanual shift mode in which the gear stage is established by a manualshift operation. The shift mode is manually selected between theautomatic shift mode and the manual shift mode. Further the gear stageupon selection of the shift mode from the automatic shift mode to themanual shift mode is set based on a second vehicle operation informationwhich is different from the first vehicle operation information.

According to the embodiment, at the automatic shift mode, the gear stageselected based on the first vehicle operation information is set in theautomatic transmission. Upon selection of the shift mode from theautomatic shift mode to the manual shift mode, the gear stage is setbased on the second vehicle operation information that is different fromthe first vehicle operation information. This makes it possible to setthe gear stage upon selection of the shift mode from the automatic shiftmode to the manual shift mode so as to be different from the gear stageset at the automatic shift mode. The gear stage desired by the vehicleoperator can be established with the reduced frequency of the manualshift operation at the manual shift mode.

In an embodiment of the invention, a shift control apparatus for avehicular automatic transmission sets an automatic shift mode in which agear stage is established based on a first vehicle operation informationused for selecting a gear stage of the automatic transmission, and amanual shift mode in which the gear stage is established by a manualshift operation. The shift mode is manually selected between theautomatic shift mode and the manual shift mode. Further the gear stageupon the manual shift operation at the manual shift mode is set based ona fourth vehicle operation information.

In the embodiment, at the automatic shift mode, the gear stage isselected based on the first vehicle operation information, and set inthe automatic transmission. Meanwhile, when the manual shift operationis performed at the manual shift mode, the gear stage selected based onthe fourth vehicle operation information is set in the automatictransmission. Accordingly, at the manual shift mode, a single manualshift operation makes it possible to set the currently set gear stage tothe one at least two stages lower or higher speed such that theappropriate driving force or the engine braking force may be obtained.

In an embodiment of the invention, a shift control apparatus for avehicular automatic transmission sets an automatic shift mode in which agear stage is established based on a first vehicle operation informationused for selecting a gear stage of the automatic transmission, and amanual shift mode in which a shift range having the gear stageestablished based on the first vehicle operation information is selectedby a manual shift operation. The shift mode is manually selected betweenthe automatic shift mode and the manual shift mode. The shift range uponselection of the shift mode from the automatic shift mode to the manualshift mode is set based on a second vehicle operation information whichis different from the first vehicle operation information.

According to the embodiment, at the automatic shift mode, the gear stageselected based on the first vehicle operation information is set in theautomatic transmission. At the manual shift mode, the shift range havingthe gear stage to be set based on the first vehicle operationinformation by the manual shift operation is changed. When the automaticshift mode is manually changed to the manual shift mode, the shift rangeis selected based on the second vehicle operation information that isdifferent from the first vehicle operation information. This makes itpossible to set the gear stage upon change in the shift mode to themanual shift mode so as to be different from the one selected at theautomatic shift mode. As a result, the gear stage desired by the vehicleoperator can be established with the reduced frequency of the manualshift operation at the manual shift mode.

In the embodiment, the second vehicle operation information includes avehicle speed upon selection of the shift mode from the automatic shiftmode to the manual shift mode.

The embodiment makes it possible to set the gear stage that is one stagehigher than the one where higher driving force or engine braking forceis obtained in accordance with the vehicle speed upon selection of theshift mode from the automatic shift mode to the manual shift mode.Unlike the shift control apparatus in which the gear stage at the manualshift mode is at least one stage lower than the gear stage selected atthe automatic shift mode, selection of the shift mode to the manualshift mode may avoid unnecessary generation of the engine braking force.

The embodiment limits a highest gear stage set based on the firstvehicle operation information at the automatic shift mode so as to be atleast one stage lower based on a third vehicle operation information,and sets the shift range having the highest gear stage limited to be atleast one stage lower. The second vehicle operation information includesthe highest gear stage limited to be at least one stage lower.

According to the embodiment, the highest stage of the gear stageselected based on the first vehicle operation information at theautomatic shift mode is limited to be at least one stage lower based onthe third vehicle operation information. When the shift mode is changedfrom the automatic shift mode to the manual shift mode in theaforementioned stage, the shift range having the highest gearcorresponding to the limited highest gear stage is set. In the statewhere the highest gear stage is limited at the automatic shift mode, thegear stage higher than the limited highest gear stage is not establishedwhen the manual shift mode is selected. This makes it possible to selectthe gear stage where the higher driving force or the engine brakingforce is obtained only by a single downshifting operation.

In the embodiment, the third vehicle operation information includes aslope resistance to a vehicle that runs one of uphill and downhill,based on which the highest gear stage is limited to be at least onestage lower.

According to the embodiment, the highest gear stage set at the automaticshift mode is limited to be at least one stage lower based on the sloperesistance to the vehicle that runs uphill or downhill. In the casewhere the highest gear stage is limited at the automatic shift mode uponrunning uphill or downhill, the gear stage higher than the limitedhighest gear stage is not selected upon change in the shift mode to themanual shift mode. This makes it possible to select the gear stage wherehigher torque for running uphill or the engine braking force is obtainedby a single downshifting operation at the manual shift mode.

In the embodiment, the third vehicle operation information includes oneof a temperature of cooling water and a temperature of oil for theautomatic transmission, based on which the highest gear stage is limitedto be at least one stage lower.

According to the embodiment, the highest gear stage set at the automaticshift mode is limited to be at least one stage lower based on atemperature of cooling water or a temperature of oil for the automatictransmission. This makes it possible to avoid selection of the gearstage where the engine speed insufficient to increase the cooling watertemperature or the oil temperature is obtained. This makes it possibleto select the gear stage where higher driving force or the enginebraking force is obtained by a single downshifting operation at themanual shift mode.

In an embodiment of the invention, a shift control apparatus for avehicular automatic transmission sets an automatic shift mode in which agear stage is established based on a first vehicle operation informationused for selecting a gear stage of the automatic transmission, and amanual shift mode in which a shift range having the gear stageestablished based on the first vehicle operation information is selectedby a manual shift operation. The shift mode is manually selected betweenthe automatic shift mode and the manual shift mode. Further, the shiftrange upon the manual shift operation at the manual shift mode is setbased on a fourth vehicle operation information.

According to the embodiment, when the manual shift operation isperformed at the manual shift mode, the shift range selected based onthe fourth vehicle operation information is set in the automatictransmission. This makes it possible to directly select the shift rangethat allows the gear stage to be set such that appropriate higherdriving force or the engine braking force is obtained only by a singlemanual shift operation.

In the embodiment, the manual shift operation is a downshiftingoperation, and the fourth vehicle operation information is obtained froman accelerator opening caused by the downshifting operation, a currentvehicle acceleration, and an acceleration after the manual shiftoperation at which the gear stage set upon shifting of the shift rangeto have the highest gear limited to be at least one stage lower isestablished.

According to the embodiment, the fourth vehicle operation information isderived from the accelerator opening upon downshifting operation at themanual shift mode, the vehicle acceleration, and the acceleration aftershifting detected upon establishment of the gear stage to be set uponshifting down to the shift range having the highest gear as being atleast one stage lower. The shift range set upon the downshifting isselected based on the fourth vehicle operation information. The shiftrange set by a single downshifting operation may be selected based onthe intention of the vehicle operator to accelerate which is estimatedfrom the accelerator opening, the current vehicle running state, and thevehicle running state upon shifting down to the shift range.

The embodiment limits a highest gear stage set by the manual shiftoperation at the manual shift mode so as to be at least one stage lowerthan the highest gear in the shift range based on a third vehicleoperation information, and sets the shift range having a highest gearstage that is one stage lower than the limited highest gear stage setupon the downshifting operation performed by the manual shift operation.The fourth vehicle operation information includes the highest gear stagelimited to be at least one stage lower.

According to the embodiment, the highest gear stage of the shift rangeset by the manual shift operation is limited to be at least one stagelower than the highest gear stage based on the third vehicle operationinformation. When downshifting is performed in the aforementioned state,the shift range having the highest gear stage as being one stage lowerthan the limited highest gear is selected. Even if the highest gearstage of the shift range set at the manual shift mode is limited to beat least one stage lower, downshifting to the gear stage where higherdriving force or higher engine braking force can be obtained isperformed by a single downshifting operation. When the highest gearstage selected in the shift range set at the manual shift mode is notlimited, the shift range is shifted down to the one having the highestgear stage as being one stage lower at every downshifting operation.

In the embodiment, the third vehicle operation information includes aslope resistance to the vehicle that runs one of uphill and downhill.The embodiment limits the highest gear stage to be at least one stagelower than the highest gear stage in the shift range based on the sloperesistance.

According to the embodiment, the highest gear stage of the shift rangeset by the manual shift operation is limited to the stage that is lowerthan the highest gear stage based on the slope resistance of the vehiclethat runs uphill or downhill. As a result, even if the highest gearstage of the shift range set at the manual shift mode is limited,downshifting to the gear stage where higher driving force for runninguphill or higher engine braking force can be obtained is performed by asingle downshifting operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart representing a control routine for setting a firstshift range in a first embodiment;

FIG. 2 is a block diagram of an automatic transmission;

FIG. 3 is a block diagram of an electric system of the automatictransmission;

FIG. 4 is a schematic view showing shift positions provided in a shiftdevice;

FIG. 5 is a table representing gear speeds that can be selected in therespective shift ranges D, 2 and L;

FIG. 6 is a schematic view showing the state where the shift range isselected in the position M;

FIG. 7 is a table representing gear speeds that can be selected in therespective shift ranges;

FIG. 8 is a flowchart representing a control routine for setting asecond shift range in a second embodiment;

FIG. 9 is a block diagram of an automatic transmission system in a thirdembodiment;

FIG. 10 is a flowchart representing a control routine for setting athird shift range;

FIG. 11 is a flowchart representing a control routine for setting thethird shift range;

FIG. 12 is a flowchart representing a control routine for setting thethird shift range;

FIG. 13 is a flowchart representing a control routine for setting afourth shift range in a fourth embodiment;

FIG. 14 is a flowchart representing a control routine for setting athird shift range in other embodiment;

FIGS. 15A and 15B are flowcharts representing control routines forsetting the first shift range in other embodiment; and

FIG. 16 is a schematic view of the shift device according to otherembodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS First Embodiment

A first embodiment of the invention will be described referring to FIGS.1 to 7. Referring to FIG. 2, an automatic transmission system 10 mountedin a vehicle includes an automatic transmission 11, a shift device 12,an upshift switch 13, a downshift switch 14, and an electronic controlunit for transmission 15 (hereinafter referred as a T-ECU).

The automatic transmission 11 receives an output of a gasoline engine(an internal combustion engine that is referred simply as the engine) 16via a torque converter 17 so as to be output to a drivetrain (notshown).

The automatic transmission 11 includes a gear portion 18 and a hydrauliccontrol 19. The gear portion 18 includes a plurality of frictionengagement elements such as hydraulic clutches and hydraulic brakes inaddition to the gear train of a planetary gear type. The gear trainconnection state is changed to a parking state, reverse state, neutralstate, and a forward state by selecting combination of the frictionengagement elements to be operated. In the forward state, the gear stageto be established is selected among those speeds including 1st, 2nd,3rd, 4th, and 5th shift speeds.

A hydraulic control 19 includes a plurality of electromagnetic solenoidseach operated on the basis of control signals input from outside. Eachoperation state of the hydraulic clutches and the hydraulic brakes ischanged in accordance with the operating state of each of theelectromagnetic solenoids. The operating state of the gear portion 18is, then, changed to one of the parking state, reverse state, neutralstate, and forward state.

The shift device 12, provided aside a driver's seat, includes a shiftlever 20 by which the operating state of the automatic transmission 11is selected to one of the parking state, reverse state, neutral stateand forward state.

Referring to FIG. 4, the shift device 12 has a shift gate provided withshift positions including P (parking), R (reverse), N (neutral), D(drive range), M (manual range), 2 (two-speed range), and L (one-speedrange) such that the shift position is selected by the shift lever 20.

Referring to FIG. 2, the upshift switch 13 and the downshift switch 14are provided on the left and the right portions of a steering wheel 21,respectively. Those upshift and downshift switches 13, 14 are providedso as to be operated by the vehicle operator during the steeringoperation. The upshift switch 13 is operated by the vehicle operator tointentionally perform upshifting to establsh the gear to be one stagehigher in the state where the position M of the shift device 12 isselected. Likewise the downshift switch 14 is operated by the vehicleoperator to intentionally perform downshifting to establish the gear tobe one stage lower in the state where the position M of the shift device12 is selected.

An electrical system of the embodiment will be described referring toFIG. 2. The engine 16 is provided with a water temperature sensor 22 fordetecting a temperature TW of an engine cooling water.

An intake pipe 23 is provided with a throttle opening sensor 25 fordetecting a throttle opening TH of a throttle valve 24. The automatictransmission 11 is provided with a vehicle speed sensor 26.

According to the embodiment, the throttle opening TH and the vehiclespeed V constitute the first vehicle operation information, and thevehicle speed V constitutes the second vehicle operation information.The shift device 12 is provided with a shift position sensor 27 fordetecting a shift position SP.

Referring to FIG. 3, the T-ECU 15 receives operation signals from theupshift switch 13 and the downshift switch 14, respectively, and furtherdetection signals from the water temperature sensor 22, throttle openingsensor 25, vehicle speed sensor 26, and shift position sensor 27.

Meanwhile, the T-ECU 15 outputs control signals indicating the operatingstate to be established, and control signals indicating the gear stageto be connected in the forward shift speeds to the hydraulic controlportion 19 of the automatic transmission 11. In the embodiment, theT-ECU 15 serves to set the gear stage and the shift range upon change inthe shift mode.

The T-ECU 15 changes the operation state of the gear portion 18 bycontrolling the hydraulic control 19 of the automatic transmission 11 onthe basis of the shift position SP detected by the shift position sensor27.

More specifically, the T-ECU 15 brings the gear portion 18 into theparking state when the shift position SP is detected as being in theposition P. Likewise, it brings the gear portion 18 into the reverseposition and the neutral position when the shift position SP is detectedas being the positions R and N, respectively.

The T-ECU 15 selects the shift mode into the automatic shift mode whenthe shift position SP is in the position D, and selects the gear stageamong the 1st to 5th speeds at which it is expected to provideappropriate fuel efficiency and power in accordance with the vehicleoperating state. Accordingly, the gear stage is automatically changed tothe selected speed.

According to the embodiment, the vehicle operating state (engine load,torque required by the vehicle operator and the like) is determined onthe basis of the vehicle speed V and the throttle opening TH under thegenerally employed automatic shift control so as to select the gearstage that has been preliminarily set in accordance with the vehicleoperating state. In the embodiment, the vehicle speed V and the throttlevalve opening TH constitute the first vehicle operating information.

When the shift position SP is in the position 2, the T-ECU 15 does notperform upshifting from the 2nd to the higher speed. The T-ECU 15conducts automatic transmission control as in the automatic shift modein the shift range having the 2nd speed as the highest gear stage inaccordance with the vehicle operating state as shown in FIG. 5.

When the shift position SP is in the position L, the T-ECU 15 holds thegear stage in the 1st speed. Meanwhile, when the shift position SP is inthe position M, the manual shift mode is set, and the shift range ischanged on the basis of the upshifting SU by the upshift switch 13 orthe downshifting operation SD by the downshift switch 14. The shiftrange includes 5 ranges, that is, ranges 5, 4, 3, 2 and L. Referring toFIG. 7, the range 5 allows selection of the gear stage among 1st to 5thspeeds. Each of the ranges 4, 3, 2 allows selection of the gear stageamong 1st to 4th speeds, 1st to 3rd speeds, and 1st to 2nd speeds,respectively. In the range L, the 1st speed is only available. The T-ECU15 conducts the shift control of range holding type in the manual shiftmode. In the embodiment, the upshifting SU and the downshifting SD aremanually conducted.

When the upshifting SU is performed in the manual shift mode, the T-ECU15 changes the currently set shift range to the shift range having thehighest gear which is one stage hither than the highest gear in thecurrent shift range. Referring to FIG. 6, for example, if the shiftrange is currently set in L, the shift range is changed to the range 2.Likewise, if the shift range is currently set in the range 2, the shiftrange is changed to the range 3. If the shift range is currently set inthe range 3, the shift range is changed to the range 4. If the shiftrange is currently set in the range 4, the shift range is changed to therange 5.

When the downshifting SD is performed, the T-ECU 15 changes thecurrently set shift range to the shift range having the highest gear asbeing one stage lower than the highest gear in the currently set shiftrange. That is, as shown in FIG. 6, if the shift range is currently setin the range 5, the shift range is changed to the range 4. Likewise, ifthe shift range is currently set in the range 4, the shift range ischanged to the range 3. If the shift range is currently set in the range3, the shift range is changed to the range 2. If the shift range iscurrently set in the range 2, the shift range is changed to the range L.

In the currently set shift range in the manual shift mode, the T-ECU 15conducts the same automatic shift control as those conducted in theposition D in the automatic shift mode. If the shift range 5 iscurrently set, the gear stage is selected among the 1st to the 5thspeeds in accordance with the throttle opening TH and the vehicle speedV as shown in the table of FIG. 7. If the shift range 4 is currentlyset, the gear stage is selected among the 1st to the 4th speeds. If theshift range 3 is currently set, the gear stage is selected among the 1stto the 3rd speeds. If the shift range 2 is currently set, the gear stageis selected between the 1st and 2nd speeds. If the shift range L iscurrently set, the gear stage is held in the 1st stage irrespective ofthe throttle opening TH and the vehicle speed V. When the automaticshift control is conducted in the ranges L, 2, 3, and 4 at the manualshift mode, the upshifting operation from the highest gear stage in thecurrently set shift range is stopped unlike the automatic shift controlat the automatic shift mode.

(Control for Setting First Shift Range)

Upon selection of the shift position SP from the position D to M, theT-ECU 15 performs the control for setting the first shift range wherethe shift range after setting the shift position is selected among 5shift ranges on the basis of the vehicle speed V. In this embodiment,the vehicle speed V constitutes the second vehicle operationinformation.

The control for setting the first shift range will be describedreferring to the flowchart of FIG. 1. In step (hereinafter referred toas S) 100, it is determined whether the shift position SP is set in theposition M. If YES is obtained in S100, that is, the shift position SPis set in the position M, the shift mode is held in the manual mode,thus keeping the manual shift control.

If NO is obtained in S100, that is, the shift position SP is set in theposition D, the process proceeds to S101 where the shift mode is changedfrom manual to automatic mode, thus, executing the automatic shiftcontrol and the process proceeds to S102. In the automatic shift mode,in S102, it is determined whether the vehicle speed V is smaller than apredetermined first vehicle speed reference value SPDCHK1. If YES isobtained in S102, that is, the vehicle speed V is smaller than theSPDCHK1, the process proceeds to step S103 where the 3 range flagsftch3RG is set to 1, and the 4 range flag sftch4RG and the 5 range flagsftch5RG are set to 0, respectively. The first vehicle speed referencevalue SPDCHK1 represents the value based on which it is determinedwhether the currently detected vehicle speed V allows selection of oneof the 3rd and 4th speeds under the automatic shift control in theautomatic shift mode. The 3 range flag sftch3RG, 4 range flag sftch4RG,and 5 range flag sftch5RG are used for setting the shift ranges 3, 4,and 5, respectively.

If the vehicle speed V is equal to or higher than the first vehiclespeed reference value SPDCHK1 in S103, the process proceeds to S104where it is determined whether the vehicle speed V is smaller than asecond vehicle speed reference value SPDCHK2 that is larger than thefirst vehicle speed reference value SPDCHK1. If YES is obtained in S104,that is, the vehicle speed is lower than the SPDCHK2, the processproceeds to S105 where the 4 range flag sftch4RG is set to 1, and the 3range flag sftch3RG, and the 5 range flag sftch3RG are set to 0,respectively. The second vehicle speed reference value SPDCHK2represents the value based on which it is determined whether thecurrently detected vehicle speed V allows selection of one of the 4thand the 5th speeds under the automatic shift control in the automaticshift mode.

If NO is obtained in S104, that is, the vehicle speed V is equal to orhigher than the SPDCHK2, the process proceeds to S106 where the 5 rangeflag sftch5RG is set to 1, and the 3 range flag sftch3RG, 4 range flagsftch4RG are set to 0, respectively.

After executing S103, S105, and S106, the process proceeds to S107 whereit is determined whether the shift position SP has been changed from theposition D to M. If NO is obtained in S107, that is, the shift positionSP is held in the position D, the process returns to S101.

If YES is obtained in S107, that is, the shift position SP has beenchanged to the position M, the process proceeds to S108 where it isdetermined whether the 3 range flag sftch3RG is set to 1. If YES isobtained in S108, that is, the sftch3RG is equal to 1, the processproceeds to S109 where the shift range is changed to the range 3, andthe 3 range flag sftch3RG is set to 0. The routine, then, ends.

If NO is obtained in S108, that is, the 3 range flag sftch3RG is notequal to 1, the process proceeds to S110 where it is determined whetherthe 4 range flag sftch4RG is equal to 1. If YES is obtained in S110,that is, the sftch4RG is equal to 1, the process proceeds to S110 wherethe shift range is changed to the range 4, and the 4 range flag sftch4RGis set to 0. The routine, then ends.

If NO is obtained in S110, that is, the 4 range flag sftch4RG is notequal to 1, the process proceeds to S112 where the shift range ischanged to the range 5, and the 5 range flag sftch5RG is set to 0. Theroutine, then ends.

(Operation)

The operation of the embodiment as structured above will be described.

When the vehicle operator sets the shift position SP to the position Dwhere the 3rd speed is established under the automatic shift control,that is, the accelerator pedal is released during running at the vehiclespeed V as a constant speed, which is lower than the first vehicle speedreference value SPDCHK1, the throttle opening TH is fully closed.Accordingly, the upshifting from the 3rd to the 5th speed is performed.

If the vehicle operator intends to perform downshifting for the purposeof obtaining the engine braking force higher than that obtained in the5th speed, the shift position SP is changed from the position D to M.Then the shift range in the position M becomes the range 3 such that thegear stage is changed from the 5th to the 3rd speed.

In the aforementioned state, when the vehicle operator performsdownshifting SD once, the shift range is changed from the range 3 to 2such that the gear stage is changed from the 3rd to the 2nd speed. Thismakes it possible to provide the engine braking force higher than thatobtained in the one stage lower gear, that is, 2nd speed during runningat the constant speed in the state where the 3rd speed is selected underthe automatic shift control.

When the vehicle operator sets the shift position SP to the position D,and the 5th speed is selected in the automatic shift mode, that is, theaccelerator pedal is released during running at the high vehicle speed Vwhich is equal to or higher than the second vehicle speed referencevalue SPDCHK2, the 5th speed is maintained.

If the vehicle operator intends to perform downshifting for the purposeof obtaining the acceleration torque or the engine braking force higherthan that obtained in the 5th speed, the shift position SP is changedfrom the position D to M. Then the shift range in the position M becomesthe range 5 such that the gear stage is kept in the 5th speed.

In the aforementioned state, when the vehicle operator performsdownshifting SD once, the shift range is changed from the range 5 to 4such that the gear stage is changed from the 5th to the 4th speed. Thismakes it possible to provide the acceleration torque or the enginebraking force during running at high speeds in the 5th speed under theautomatic shift control, which is higher than that obtained in one stagelower speed, that is, the 4th speed.

Accordingly only a single downshifting after change in the mode from theautomatic shift mode to the manual shift mode allows the gear stage setat the automatic shift mode to be shifted down to the stage as being onestage lower.

(Effect)

Effects obtained from the embodiment will be described.

(1) In the automatic shift mode where the shift position SP is set tothe position D, the T-ECU 15 selects the gear stage among 5 speeds so asto be set in the automatic transmission 11 on the basis of the throttleopening TH and the vehicle speed V detected at that time (first vehicleinformation).

Upon change in the shift position SP from the position D to M, the T-ECU15 sets the shift range selected in accordance with the vehicle speed Vdetected at that time (second vehicle information) in the automatictransmission 11.

Since the gear stage set in the manual shift mode is different from thegear stage set in the automatic shift mode, the vehicle operator isallowed to downshift to the gear at which the engine braking forcehigher than the desired force while reducing the frequency ofdownshifting operations at the manual shift mode.

In the shift control apparatus for the vehicular automatic transmissiondisclosed in JP-A-6-221417, when the vehicle operator releases theaccelerator pedal in order to decelerate from the running state ofacceleration in the 3rd speed at the automatic shift mode, the shiftcontrol apparatus automatically performs upshifting from the 3rd to the5th speed. When the vehicle operator changes the shift range from therange D to B for further deceleration, the gear is shifted from the 5thto the 4th speed. The engine braking force desired by the vehicleoperator is obtained in the 2nd speed that is one stage lower than the3rd speed. Therefore, downshifting has to be performed twice in therange B.

In this embodiment, on the contrary, the downshifting SD is requiredonly once after changing the shift mode to the manual mode.

(2) In the manual shift mode, the T-ECU 15 selects the appropriate gearin the shift range set upon selection from the automatic shift mode tothe manual shift mode in accordance with the throttle opening TH and thevehicle speed V (first vehicle operation information), and sets theselected gear in the automatic transmission 11.

The T-ECU 15 changes the currently set shift range to the one having thehighest gear that is one stage higher than that in the currently setshift range by the upshifting SU at the manual shift mode. Likewise theT-ECU 15 changes the currently set shift range to the one having thehighest gear that is one stage lower than that in the currently setshift range by the downshifting SD.

Therefore, during running at the manual shift mode, the gear stage isautomatically downshifted in accordance with the vehicle operationstate. If the vehicle is decelerated without applying further higherengine braking force by downshifting, the downshifting is automaticallyperformed. This makes it possible to eliminate the need of performingthe downshifting, thus simplifying the operation.

(3) When the vehicle operator changes the shift mode from the automaticmode to the manual mode, the T-ECU 15 selects the gear in accordancewith the vehicle speed V (second vehicle operation information) and setsthe selected gear in the automatic transmission 11.

If the automatic shift mode is changed to the manual shift mode duringrunning at the automatic shift mode in the state where the upshiftingfrom the currently set gear is performed by the vehicle operator whoreleases the accelerator pedal, the gear established after the change inthe shift mode corresponds to the one which has been set based on thethrottle opening TH and the vehicle speed under the automatic shiftcontrol before the release of the accelerator pedal.

The appropriate gear in accordance with the vehicle speed V upon changein the shift mode to the manual mode can be established irrespective ofthe release state of the accelerator pedal in the automatic shift mode.Only a single operation of the downshifting at the automatic shift modemakes it possible to change the gear to the stage at which the enginebraking force or the acceleration torque that is higher than thatdesired by the vehicle operator is obtained.

Second Embodiment

A second embodiment of the invention will be described referring to FIG.8. The second embodiment is different from the first embodiment in threepoints as described below.

In the second embodiment, the automatic transmission includes 6 speeds.

The uphill/downhill control is conducted in the automatic shift mode.

The second shift range set control is conducted in place of the firstshift range set control.

The elements constituting the structure, which are identical to those inthe first embodiment will be designated with the same referencenumerals, and each explanation of those elements, thus, will be omitted.The explanation of the aforementioned three different points areexplained hereinafter.

In the second embodiment, the T-ECU 15 serves to set the gear stage uponmanual shifting, set the shift range upon manual shift mode, andrestrict shifting in the automatic shift mode. In the automatic shiftmode where the shift position is set in the position D, the T-ECU 15selects the appropriate gear among the 1.sup.st to 6.sup.th speeds so asto obtain the fuel efficiency and power in accordance with the vehicleoperation state. The T-ECU 15 then sets the selected gear to beestablished for conducting automatic shift control. Like the firstembodiment, the gear is selected on the basis of the first vehicleoperation information containing the vehicle speed V and the throttleopening TH.

When the shift position SP is in the position M, the shift mode ischanged to the manual shift mode. In the aforementioned state, the T-ECU15 changes the shift range to be set in accordance with the upshiftingSU or downshifting SD. In this embodiment, 6 shift ranges are providedby adding one shift range to the 5 shift ranges in the first embodiment.The shift range 6 includes the 1st to 6th speeds. Upon selection of theshift mode to the manual mode, if the shift range 5 has been set, theT-ECU 15 performs upshifting so as to change the shift range from therange 5 to 6. If the shift range 6 has been set, the T-ECU 15 performsdownshifting so as to change the shift range from the range 6 to 5. Ifthe shift range 6 has been set in the manual shift mode, the T-ECU 15selects the appropriate gear among the 1st to 6th speeds and sets theselected gear in the automatic transmission 11 in accordance with thevehicle operation state.

(Uphill/Downhill Running Control)

When the vehicle is running on the uphill/downhill at the automaticshift mode, the T-ECU 15 conducts the uphill/downhill running controlsuch that the highest gear to be set is kept lower stage in accordancewith the slope resistance.

The uphill/downhill running control is a generally employed technology.In this embodiment, the slope resistance caused by running on theuphill/downhill is detected on the basis of the throttle opening TH andthe vehicle acceleration derived from the vehicle speed V. The sloperesistance caused by the running on the uphill/downhill constitutes thethird vehicle operation information.

More specifically, when the detected value (positive) of the sloperesistance during running on the uphill becomes equal to or greater thana predetermined first slope reference value, the highest gear stage isset to the 5th speed. Then upshifting from the 5th to 6th speed isinterrupted, and downshifting from the 6th to 5th speed is performed.When the detected value becomes equal to or greater than a second slopereference value that is larger than the first slope reference value, thehighest gear is set to the 4th speed. Then upshifting from the 4th tothe 5th speed is interrupted and downshifting from the 5th or 6th to 4thspeed is performed. When the detected value becomes equal to or greaterthan a third slope reference value that is larger than the second slopereference value, the highest gear is set to the 3rd speed. Thenupshifting from the 3rd to 4th speed is interrupted and downshiftingfrom the 4th, 5th, or 6th to 3rd speed is performed.

When the detected value (negative) of the slope resistance duringrunning on the downhill becomes equal to or greater than a predeterminedfourth slope reference value, the highest gear is set to the 5th speed.The upshifting from the 5th to 6th speed is interrupted, anddownshifting from the 6th to 5th is performed. When the detected valuebecomes equal to or greater than a fifth slope reference value that islarger than the fourth slope reference value, the highest gear is set tothe 4th speed. Then upshifting from the 4th to 5th speed is interrupted,and downshifting from the 5th or 6th to 4th speed is performed. When thedetected value becomes equal to or greater than a sixth slope referencevalue larger than the fifth slope reference value, the highest gear isset to the 3rd speed. Then upshifting from the 3rd to 4th speed isinterrupted, and downshifting from the 4th, 5th or 6th to 3rd speed isperformed.

Upon change in the shift position SP from the position D to M under theuphill/downhill running control at the automatic shift mode, the T-ECU15 executes a second shift range set control for setting the shift rangehaving the highest gear stage that is limited to the lower speed underthe uphill/downhill running control.

In the second embodiment of the invention, the highest gear stage to belimited under the uphill/downhill running control constitutes the secondvehicle operation information.

(Second Shift Range Set Control)

The control routine for the second shift range set control will bedescribed referring to a flowchart of FIG. 8. In S200, it is determinedwhether the shift position SP is in the position M. If YES is obtainedin S200, that is, the shift position SP is in the position M, the shiftmode is held at the manual shift mode where the manual shift control iscontinued. If NO is obtained in S200, that is, the shift position SP isin the position D, the process proceeds to S201 where the shift mode ischanged from the manual to the automatic mode where the automatic shiftcontrol is executed.

Under the automatic shift control, it is determined in S202 whether thehighest gear speed is limited under the uphill/downhill running control.If NO is obtained in S202, that is, the highest gear speed is notlimited, the process proceeds to S203. In S203, the 3rd speed flagXEN3rd, 4th speed flag XEN4th, and 5th speed flag XEN5th are all set to0, and the automatic shift control is continued. The 3rd speed flagXEN3rd, 4th speed flag XEN4th, and 5th speed flag XEN5th are used forsetting the shift ranges 3, 4, and 5, respectively.

If YES is obtained in S202, that is, the highest gear speed is limited,the process proceeds to S204 where it is determined as to which gearstage, the 3rd, 4th or 5th speed, corresponds to the highest stage inthe currently set shift range.

If it is determined that the 3rd speed corresponds to the highest gearstage in S204, the process proceeds to S205 where the 3rd flag XEN3rd isset to 1. If it is determined that the 4th speed corresponds to thehighest gear stage in S204, the process proceeds to S206 where the 4thflag XEN4th is set to 1. Likewise if it is determined that the 5th speedcorresponds to the highest gear stage in S204, the process proceeds toS207 where the 5th flag XEN5th is set to 1.

After execution of S205, S206 or S207, the process proceeds to S208where it is determined whether the shift position SP is changed from theposition D to M. If NO is obtained in S208, that is, the shift positionSP is held in the position D, the routine returns to S201.

Meanwhile, if YES is obtained in S208, that is, the shift position SP ischanged from the position D to M, the process proceeds to S209 where itis determined whether the 3rd flag XEN3rd is equal to 1. If YES isobtained in S209, that is, the 3rd flag XEN3rd is equal to 1, theprocess further proceeds to S210 where the shift range is changed to therange 3, and the routine, then ends.

If NO is obtained in S209, that is, the 3rd flag XEN3rd is not equal to1, the process proceeds to S211 where it is determined whether the 4thflag XEN4th is equal to 1. If YES is obtained in S211, that is, the 4thflag XEN4th is equal to 1, the process proceeds to S212 where the shiftrange is changed to the range 4, and the routine ends.

If NO is obtained in S211, that is, the 4th flag XEN4th is not equal to1, the process proceeds to S213 where the shift range is changed to therange 5.

(Operation)

The operation of the above-structured embodiment will be describedhereinafter.

When the vehicle is running on the uphill in the state where the shiftposition is set to the position D, and the running state of the vehicleon the gentle uphill shows the slope resistance equal to or larger thanthe first slope resistance value, and smaller than the second sloperesistance value, the highest gear is limited to the 5th speed under theuphill running control.

In the case where the vehicle operator intends to perform downshiftingto obtain the uphill running torque higher than that obtained in the 5thspeed, the shift position is changed from the position D to M. Then thesecond shift range set control is executed such that the shift range 5in the position M is established, thus maintaining the gear stage in the5th speed.

When the vehicle operator performs downshifting only once in theaforementioned case, the shift range 5 is changed to the shift range 4,and the gear stage is shifted from the 5th to 4th speed. As a result,during running on the gentle uphill under the uphill running controlwhere the 5th speed is set as the highest gear in the shift range, theuphill running torque that is higher than the torque derived from the4th speed as being one stage lower can be obtained.

In the medium uphill running at the automatic shift mode showing theslope resistance equal to or larger than the second slope resistancereference value, and smaller than the third slope resistance referencevalue, the uphill running control limits the highest gear in the shiftrange to the 4th speed.

When the vehicle operator intends to perform downshifting to obtain theuphill running torque higher than the torque obtained in the 4th speed,the shift position SP is changed from the position D to M. Then thesecond shift range set control starts to set the shift range to therange 4 at the shift position M. The gear stage is, thus, held in the4th speed.

If the vehicle operator performs downshifting only once, the shift rangeis changed from the range 4 to 3, and the gear stage is shifted from the4th to the 3rd speed. As a result, during running on the medium uphillhaving the 4th speed set as the highest gear stage under the uphillrunning control, the uphill torque that is higher than the torquederived from the 3rd speed as being one stage lower can be obtained.

In the running on the sharp uphill at the automatic shift mode, when theslope resistance is equal to or larger than the third slope resistancereference value, the uphill running control limits the highest gear inthe shift range to the 3rd speed.

When the vehicle operator intends to perform downshifting to obtain theuphill running torque higher than the torque derived from the 3rd speed,the shift position SP is changed from the position D to M.

Then the second shift range set control starts to set the shift range tothe range 3 in the position M. The gear stage is, thus, held in the 3rdspeed. If the vehicle operator performs downshifting only once in theaforementioned state, the shift range is changed from the range 3 to 2,and the gear stage is shifted from the 3rd to 2nd speed.

As a result, during running on the sharp uphill where the 3rd speed isset as the highest gear stage under the uphill running control, theuphill torque that is higher than the torque derived from the 2nd speedas being one stage lower can be obtained. As a result, a singledownshifting operation after changing the shift mode from the automaticto manual mode makes it possible to perform downshifting from the gearstage set at the automatic shift mode to the gear that is one stagelower.

During running downhill, like running uphill as described above, singledownshifting operation of the vehicle operator makes it possible toperform downshifting to the gear as being one stage lower. Accordingly,the engine braking force higher than the one derived from the gear stageone stage lower can be obtained.

(Effect)

The effect of the embodiment will be described hereinafter.

(4) When the vehicle operator changes the shift mode from the automaticto the manual mode, the T-ECU 15 sets the shift range having the highestgear stage corresponding to the highest gear stage limited under theuphill/downhill running control (third vehicle operation information).

Accordingly even if the highest gear set under the uphill/downhillrunning control at the automatic shift mode is different from that atthe manual shift mode, the highest gear limited under theuphill/downhill running control can be set upon change in the shift modeto the manual mode.

Therefore, a single downshifting SD after changing the shift mode to themanual mode makes it possible to change the gear to the stage by whichthe uphill running torque higher than that intended by the vehicleoperator may be obtained.

Third Embodiment

The third embodiment of the invention will be described referring toFIGS. 9, 10, and 12 will be described hereinafter. This embodiment isdifferent from the first embodiment in the points as described below.

In the embodiment, an engine speed sensor 30, an intake air quantitysensor 31, and an accelerator opening sensor 33 are provided.

The T-ECU 15 executes a third shift range set control in the manualshift mode.

The elements constituting the structure, which are identical to those inthe first embodiment will be designated with the same referencenumerals, and each explanation of those elements, therefore, will beomitted. The explanation of the aforementioned two different points willbe explained hereinafter.

Referring to FIG. 9, the engine 16 is provided with the engine speedsensor 30 for detecting an engine speed NE. The intake air quantitysensor 31 for detecting intake air quantity Vf for air combustion isprovided in an inlet of an intake pipe 23.

An accelerator opening sensor 33 for detecting an accelerator openingtap is provided on an accelerator pedal 32. In this embodiment, theT-ECU 15 serves to set the gear stage and the shift range upon manualshifting.

The T-ECU 15 obtains the engine speed NE from the detection signaloutput from the engine speed sensor 30. The T-ECU 15 further obtains theintake air quantity Vf and the accelerator opening tap from thedetection signals output from the intake air quantity sensor 31 and theaccelerator opening sensor 33, respectively.

The T-ECU 15 obtains a current vehicle acceleration gbef of the vehiclefrom the vehicle speed V obtained at sufficiently short time intervals.The T-ECU 15 further obtains the engine torque from the engine speed NEand the intake air quantity Vf.

The T-ECU 15 estimates the acceleration gaf after shifting based on thegear ratio to be set in the shift range having the highest gear as beingone stage or two stages lower than the highest gear in the shift rangeset in accordance with the detected engine torque, and vehicle speed Vat the manual shift mode, or the transmission ratio of the powertransmission system.

In the embodiment, the T-ECU 15 executes the third shift range setcontrol for setting the shift range at which the downshifting SD isperformed at the manual shift mode on the basis of the acceleratoropening tap, the vehicle acceleration gbef, and the acceleration aftershifting gaf.

In this embodiment, the fourth vehicle operation information is obtainedfrom the accelerator opening tap, the vehicle acceleration gbef, and thevehicle acceleration gbef. Under the third shift range set control, theT-ECU 15 determines whether the vehicle operator intends to acceleratethe vehicle on the basis of the accelerator opening tap. It is furtherdetermined whether the vehicle is currently in the accelerated state,the normal running state, or the decelerated state from the vehicleacceleration gbef corresponding to the accelerator opening tap. TheT-ECU 15 estimates as to which state the vehicle is brought into aftershifting, the accelerated state, the normal running state or thedecelerated state on the basis of the acceleration after shifting gafcorresponding to the accelerator opening tap. In accordance with theaforementioned determinations, the shift range to be set upondownshifting SD is set.

(Third Shift Range Set Control)

The routine of the third shift range set control will be describedreferring to flowcharts of FIGS. 10 to 12.

In S300, it is determined whether the shift mode is in the manual modeon the basis of the shift position SP. If NO is obtained in S300, thatis, the shift mode is not at the manual mode, the control routine is notexecuted. If YES is obtained in S300, that is, the shift mode is at themanual mode, the process proceeds to S301 where it is determined whetherthe accelerator opening tap is smaller than a predetermined acceleratoropening reference value tap 1. The accelerator opening reference valuetap 1 is set such that it is determined whether the accelerator pedal 32is depressed by the vehicle operator for the purpose of accelerating thevehicle. In S301, it is determined whether the accelerator pedal 32 isdepressed by the vehicle operator who intends to accelerate the vehicle.

(No Intention of Acceleration)

If YES is obtained in S301, that is, the accelerator opening tap issmaller than the accelerator opening reference value tap 1, the processproceeds to S302 where a non-acceleration flag tapcst is set to 1.

Then in S303, it is determined whether the vehicle acceleration gbefexceeds a predetermined first acceleration reference value in anon-acceleration state regg1. The first acceleration reference valueregg1 is set such that it is determined whether the vehicle accelerationgbef resulting from depression of the accelerator pedal 32 by thevehicle operator with no intention of acceleration is relatively large.In S303, it is determined whether the vehicle acceleration gbefdetermined by the driving force and running resistance generated whenthe vehicle operator depresses the accelerator pedal 32 lightly becauseof no intention of accelerating is relatively large. The runningresistance is obtained as the sum of the air resistance in accordancewith the vehicle speed V, the slope resistance in accordance with theslope of the road, and the like.

If NO is obtained in S303, that is, the vehicle acceleration gbef isequal to or greater than the first acceleration reference value regg1,the process proceeds to S304 where the first acceleration flag in thenon-accelerated state gbefidac is set to 0. The process then proceeds toS305.

In S305, it is determined whether the acceleration gaf obtained in thegear set upon change in the currently set shift range to the range (Xrange) having the highest gear one stage lower is smaller than apredetermined second acceleration reference value in the non-acceleratedstate dcafg. The second acceleration reference value dcafg is set fordetermining relative magnitude of the acceleration after shifting gafobtained in the gear in the shift range having the highest gear as beingone stage lower. In S305, it is determined whether the magnitude of theacceleration gaf defined by the driving force and the running resistancegenerated during running by the vehicle operator with no intention ofacceleration is large.

The gear stage established upon change in the shift range to the rangehaving the highest gear as being one stage lower may become one stagelower than the currently set gear stage, or the same as the currentlyset gear stage. In the state where the highest gear stage is set in thecurrent shift range, shifting to the lower shift range may establish thegear stage as being one stage lower. In the state where the gear stageis set to be lower than the highest gear in the current shift range,shifting to the lower shift range may keep the currently set gear stageunchanged.

If YES is obtained in S305, that is, the acceleration gaf obtained inthe gear set in the shift range having the highest gear as being onestage lower is smaller than the second acceleration reference valuedcafg, the process proceeds to S306. In S306, the second accelerationflag in the non-accelerated state gafiddc is set to 1, and the processproceeds to S308. If NO is obtained in S305, the process proceeds toS307 where the second acceleration flag gafiddc is set to 0, and theprocess proceeds to S308.

If YES is obtained in S303, that is, the vehicle acceleration gbefexceeds the first acceleration reference value regg1, the processproceeds to S309 where the first acceleration flag in thenon-accelerated state is set to 1. Then the process proceeds to S310.

In S310, it is determined whether the acceleration gaf in the gear stageestablished after changing the shift range to the range having thehighest gear two stages lower, that is, the range X-1 is smaller thanthe second acceleration reference value dcafg. The second accelerationreference value in the non-accelerated state dcafg is used to determinethe relative magnitude of the acceleration gaf obtained in the gear inthe shift range having the highest gear as being two stages lower. LikeS305, it is determined in S310, whether the acceleration gaf defined bythe driving force and the running resistance is relatively large.

The gear stage established upon change in the shift range to the rangehaving the highest gear as being two stages lower by the downshifting SDmay become one stage or two stages lower than the gear which isestablished in the currently set shift range, or the same as the gearwhich is established in the currently set shift range. In the statewhere the highest gear stage or the stage one stage lower is establishedin the current shift range, shifting to the lower shift range mayestablish the gear stage as being two stages or one stage lower. In thestate where the gear stage is set to be two or more stages lower thanthe highest gear in the current shift range, shifting to the lower shiftrange may keep the currently set gear stage unchanged.

If YES is obtained in S310, that is, the acceleration gaf obtained inthe gear stage set in the shift range having the highest gear as beingtwo stages lower is smaller than the second acceleration reference valuedcafg, the process proceeds to S306. In S306, the second accelerationflag gafiddc is set to 1, and then the process proceeds to S308. If NOis obtained in S310, that is, the acceleration gaf is equal to orgreater than the second acceleration reference value dcafg, the processproceeds to S307 where the range set flag in the non-accelerated stategafidde is set to 0, and further proceeds to S308.

(Intention of Vehicle Operator to Accelerate)

If NO is obtained in S301, that is, the accelerator opening tap is equalto or greater than the accelerator opening reference value tap 1, theprocess proceeds to S311 as shown in the flowchart of FIG. 11 where thenon accelerating flag tapcst is set to 0.

Then in S312, it is determined whether the vehicle acceleration gbefexceeds a predetermined first acceleration reference value uponacceleration regg2. The first acceleration reference value regg2 is setso as to determine the relative magnitude of the vehicle accelerationgbef when the vehicle operator depresses the accelerator pedal 32 withthe intention of accelerating. In S312, it is determined whether thevehicle acceleration gbef defined by the driving force and the runningresistance caused by depression of the accelerator pedal 32 with theintention of acceleration is relatively large.

If YES is obtained in S312, that is, the current vehicle accelerationgbef is equal to or smaller than the first acceleration reference valueupon acceleration regg2, the process proceeds to S313 where the firstacceleration flag gbeftaac is set to 1, and further proceeds to S314.

In S314, it is determined whether the acceleration after shifting gafwhich is obtained in the gear stage set upon change in the shift rangeto the one having the highest gear as being one stage lower, that is,the range X becomes smaller than a predetermined second accelerationreference value upon acceleration acafg. The second accelerationreference value acafg is set such that it is determined whether theacceleration after shifting gaf, which is obtained in the gear stage setin the shift range having the highest gear as being one stage lower isrelatively large. That is, in S314, it is determined whether theacceleration gaf which is defined by the driving force and the runningresistance is relatively large when the vehicle operator has nointention to accelerate.

If YES is obtained in S314, that is, the acceleration gaf obtained inthe gear stage set in the shift range having the highest gear as beingone stage lower is larger than the second accelerator reference valueupon acceleration acafg, the process proceeds to S315. In S315, thesecond acceleration flag gaftaac is set to 1, and the process furtherproceeds to S308. If NO is obtained in S314, that is, the accelerationgaf is equal to or smaller than the second accelerator reference valueupon shifting acafg, the process proceeds to S316 where the secondacceleration flag gaftaac is set to 0, and further proceeds to S308.

If NO is obtained in S312, that is, the vehicle acceleration gbef isequal to or smaller than the regg2, the process proceeds to S317 wherethe first acceleration flag upon acceleration gbeftaac is set to 0. Theprocess then proceeds to S318.

In S318, it is determined whether the acceleration after shifting gafset upon the change from the currently set shift change to the range X-1having the highest gear as being two stages lower is smaller than thesecond reference value upon acceleration acafg. The reference valueacafg is set such that it is determined whether the acceleration aftershifting gaf obtained in the gear stage set in the shift range havingthe highest gear as being two stages lower is relatively large. LikeS314, it is determined in S318 whether the acceleration after shiftinggaf defined by the driving force and the running resistance isrelatively large when the vehicle operator has the intention toaccelerate.

If YES is obtained in S318, that is, the value gaf is greater than thereference value acafg, the process proceeds to S315 where the secondacceleration flag gaftaac is set to 1. The process then proceeds toS318.

Referring to the flowchart of FIG. 10, in S308, it is determined whetherthe downshifting SD has been performed. If NO is obtained in S308, thatis, the downshifting SD has not been performed, the process returns toS300 from where the routine is repeatedly executed. Meanwhile, if YES isobtained in S308, that is, the downshifting SD has been performed, theprocess proceeds to S319 as shown in the flowchart of FIG. 12. In S319,each state of the non-acceleration state flag tapcst, non-accelerationfirst acceleration flag gbefidac, second acceleration flag innon-acceleration state gafiddc, first acceleration flag in theacceleration state gbeftaac, and the second acceleration flag inacceleration state gaftaac is determined, respectively.

In the state where the non-acceleration state flag tapcst is set to 1and the non-acceleration first acceleration flag gbefidac is set to 0,when the second acceleration flag in non-acceleration state gafiddc isset to 1, the process proceeds to S320 where the current shift range ischanged to the shift range X-1 having the highest gear as being twostages lower.

In the state where the flag tapcst is set to 1, and the flag gbefidac isset to 1, when the flag gafiddc is set to 1, the process proceeds toS321 where the current shift range is changed to the shift range X-1having the highest gear as being two stages lower. Likewise, when theflag gafiddc is set to 0, the process proceeds to S322 where the currentshift range is changed to the shift range X-2 having the highest gear asbeing three stages lower.

In the state where the flag tapcst is set to 0, and the flag gbeftaac isset to 1, if the flag gaftaac is set to 1, the process proceeds to S321where the current shift range is changed to the shift range X having thehighest gear as being one stage lower. Likewise, when the flag gaftaacis set to 0, the process proceeds to S321 where the current shift rangeis changed to the shift range X-1 having the highest gear as being twostages lower.

In the state where the flag tapcst is set to 0, and the flag gbeftaac isset to 0, when the flag gaftaac is set to 1, the process proceeds toS321 where the current shift range is changed to the shift range X-1having the highest gear as being two stages lower. Likewise when theflag gaftaac is set to 0, the process proceeds to S322 where the currentshift range is changed to the shift range X-2 having the highest gear asbeing three stages lower.

(Operation)

An operation obtained from the above-structured embodiment will beexplained.

(No Intention of the Vehicle Operator to Accelerate)

In the case where the vehicle is running in the shift range 5 at themanual shift mode, and the 5th speed is set by the T-ECU 15 inaccordance with the current running state, when the vehicle operatorreleases the accelerator pedal 32 for deceleration or running at theconstant speed, the accelerator opening tap becomes smaller than theaccelerator operation reference value tap 1.

If the vehicle is running against the relatively large runningresistance to the vehicle driving force obtained in the 5th speed, forexample, running on the gentle downhill, the current vehicleacceleration gbef becomes equal to or smaller than the firstacceleration reference value upon acceleration regg1. That is, uponrelease of the accelerator pedal 32, a certain magnitude of the enginebraking force is applied to the vehicle, thus bringing the vehicle tothe running state at the constant speed or the decelerating speed.

In the case where the shift range is changed to the range 4 having thehighest gear as being one stage lower than the 5th speed, that is, 4thspeed, and the running resistance becomes relatively large to thevehicle driving force obtained in the 4th speed that has been changedfrom the 5th speed accordingly, the acceleration gaf becomes smallerthan the acceleration reference value dcafg. That is, downshifting tothe 4th speed may bring the vehicle into the state where higher enginebraking force is obtained such that the vehicle decelerates at furtherhigh deceleration ratio.

When the vehicle operator performs downshifting SD once in theaforementioned state highly intended to decelerate, the shift range ischanged from the range 5 to the range 4, and the gear stage isaccordingly downshifted from the 5th to 4th speed.

In the case where the vehicle runs on the gentle downhill in the 5thspeed in the selected range 5 at the manual shift mode, when the vehicleoperator performs downshifting SD once for the purpose of obtaininghigher engine braking force, the gear stage is changed from the 5th tothe 4th speed such that appropriate engine braking force is applied inaccordance with the vehicle running state.

When the running resistance is relatively small with respect to thedriving force obtained in the 4th speed as being one stage lower, theacceleration after shifting gaf becomes equal to or larger than thesecond acceleration reference value in the non-acceleration state dcafg.That is, in the aforementioned state, as the engine braking force is,not relatively high in spite of downshifting to the 4th speed, it can beestimated that the ratio of the vehicle deceleration is relatively low.

Then if the vehicle operator performs downshifting SD for the purpose ofapplying further higher deceleration, the shift range is changed fromthe range 5 to range 3, and accordingly the gear is changed from the 5thto the 3rd speed directly.

When the vehicle starts running on the relatively steep downhill in the5th speed of the range 5 at the manual shift mode, the gear stage ischanged from the 5th to the 3rd speed such that the appropriate enginebraking force is applied in accordance with the running state of thevehicle.

Upon release of the accelerator pedal 32 from the depressed state duringrunning in the 5th speed in the shift range 5, the vehicle accelerationgbef exceeds the first acceleration reference value in thenon-accelerations state regg1 when the running resistance is relativelysmall with respect to the driving force obtained in the 5th speed owingto the steep downhill. In other words, the vehicle runs in theaccelerated state even if the accelerator pedal is released.

If the running resistance in the aforementioned vehicle running state isrelatively high with respect to the driving force obtained in the 3rdspeed as being two stages lower, the acceleration after shifting gafbecomes smaller than the second acceleration reference value in thenon-acceleration state dcafg. Accordingly, it is estimated thatdownshifting to the 3rd speed may provide higher engine braking forcesuch that the vehicle is brought into the deceleration state at higherrate.

When the downshifting SD is performed once in the aforementioned stateby the vehicle operator who intends to further decelerate, the shiftrange is shifted from the range 5 to the range 3, and accordingly thegear is downshifted from the 5th to the 3rd speed.

If the vehicle operator performs the downshifting SD once for thepurpose of obtaining higher engine braking force upon running on thesteep downhill, the gear is shifted down from the 5th to the 3rd speedsuch that the appropriate engine braking force is applied in accordancewith the vehicle running state.

Meanwhile, if the running resistance is relatively low with respect tothe driving force obtained in the 3rd speed as being two stages lower,the acceleration after shifting gaf becomes equal to or larger than thesecond acceleration reference value in the non-acceleration state dcafg.That is, it is estimated that high engine braking force is not obtainedeven if the downshifting from the 5th to the 3rd speed is performed, andtherefore, the vehicle is in the state of deceleration at lower rates.

When the downshifting SD is performed once in the aforementioned stateby the vehicle operator who intends to further decelerate, the shiftrange is shifted from the range 5 to the range 2, and accordingly thegear is downshifted from the 5th to the 2nd speed.

If the vehicle operator performs the downshifting SD once for thepurpose of obtaining higher engine braking force upon running on thesteep downhill in the 5th speed in the shift range 5 at the manual shiftmode, the gear is directly shifted down from the 5th to the 2nd speed.As a result, the appropriate engine braking force is applied inaccordance with the vehicle running state.

(Intention of the Vehicle Operator to Accelerate)

In the case where the vehicle is running in the range 5 at the manualshift mode, and the 5th speed is set by the T-ECU 15 in accordance withthe current miming state, when the vehicle operator depresses theaccelerator pedal 32 for the purpose of acceleration, the acceleratoropening tap becomes equal to or larger than an accelerator operationreference value tap 1.

If the vehicle is running on the gentle uphill against the relativelysmall running resistance to the vehicle driving force obtained in the5th speed, the current vehicle acceleration gbef exceeds the firstacceleration reference value in acceleration state regg2. That is, upondepression of the accelerator pedal 32, the acceleration that is equalto or higher than a certain level is applied to the vehicle, thusbringing the vehicle into the acceleration state.

In the case where the shift range is changed to the range 4 having thehighest gear as being one stage lower than the 5th speed, that is, 4thspeed, and the running resistance becomes relatively large to thevehicle driving force obtained in the 4th speed that has been changedfrom the 5th speed accordingly, the acceleration after shifting gafexceeds the second acceleration reference value in acceleration stateacafg. That is, it is estimated that the downshifting to the 4th speedmay bring the vehicle into the state where higher acceleration isobtained so as to be applied to the vehicle.

When the vehicle operator performs the downshifting SD once in theaforementioned state for the purpose of further acceleration, the shiftrange is changed from the range 5 to the range 4, and the gear stage isaccordingly downshifted from the 5th to the 4th speed.

In the case where the vehicle runs on the gentle uphill in the 5th speedin the selected range 5 at the manual shift mode, when the vehicleoperator performs the downshifting SD once for the purpose of furtheracceleration, the gear stage is changed from the 5th to the 4th speedsuch that appropriate driving force is applied in accordance with thevehicle running state.

When the running resistance is relatively large with respect to thedriving force obtained in the 4th speed as being one stage lower, theacceleration after shifting gaf becomes equal to or smaller than thesecond acceleration reference value in the non-acceleration state acafg.That is, it is estimated that in the aforementioned state, highacceleration is not obtained even if the downshifting to the 4th speedis performed, and the vehicle acceleration is kept from being increased.

Then if the vehicle operator performs the downshifting SD for thepurpose of applying further higher acceleration, the shift range isshifted from the range 5 to range 3, and accordingly the gear isdirectly changed from the 5th to the 3rd speed.

When the vehicle operator performs the downshifting SD once forobtaining further acceleration upon running on the steep uphill, thegear is shifted from the 5th to the 3rd speed such that the appropriatedriving force is applied in accordance with the running state of thevehicle.

Upon depression of the accelerator pedal 32 during running in the 5thspeed in the range 5, the vehicle acceleration gbef becomes equal to orsmaller than the first acceleration reference value in thenon-acceleration state regg2 when the running resistance becomesrelatively large with respect to the driving force obtained in the 5thspeed upon running on the steep uphill. In other words, the vehicleacceleration is not increased even if the accelerator pedal 32 isdepressed.

If the running resistance in the aforementioned vehicle running state isrelatively small with respect to the driving force obtained in the 3rdspeed as being two stages lower, the acceleration after shifting gafexceeds the second acceleration reference value in the non-accelerationstate acafg. Accordingly, it is estimated that downshifting to the 3rdspeed may provide higher acceleration such that the vehicle is broughtinto the miming state at higher acceleration rates.

When the downshifting SD is performed once in the aforementioned stateby the vehicle operator who intends to further accelerate, the shiftrange is shifted from the range 5 to the range 3, and accordingly thegear is downshifted from the 5th to the 3rd speed.

If the vehicle operator performs the downshifting SD once for thepurpose of obtaining further acceleration upon running on the steepuphill, the gear is downshifted from the 5th to the 3rd speed such thatthe appropriate driving force in accordance with the vehicle runningstate is applied.

Meanwhile, if the running resistance is relatively large with respect tothe driving force obtained in the 3rd speed as being two stages lower,the acceleration after shifting gaf becomes equal to or smaller than thesecond acceleration reference value in the non-acceleration state acafg.That is, it is estimated that the required acceleration is not obtainedeven if the downshifting from the 5th to the 3rd speed is performed, andaccordingly the vehicle is not brought into the running state at higheracceleration rates.

When the downshifting SD is performed once in the aforementioned stateby the vehicle operator who intends to further accelerate, the shiftrange is shifted from the range 5 to the range 2, and the gear isdownshifted from the 5th to the 2nd speed.

If the vehicle operator performs the downshifting SD once for obtaininghigher acceleration upon running on the steep uphill in the 5th speed inthe shift range 5 at the manual shift mode, the gear is directlydownshifted from the 5th to the 2nd speed. As a result, the appropriatedriving force in accordance with the vehicle running state is applied.

(Effect)

The effect obtained from the above-described embodiment will beexplained.

(5) According to the embodiment, upon downshifting SD once in the statewhere the vehicle operator releases the accelerator pedal 32 duringrunning at the manual shift mode, the shift range is shifted to therange where more appropriate engine braking force is obtained. Thereforethe vehicle operator does not have to perform the downshifting SD twiceor more for establishing the gear stage in which the required higherengine braking force is obtained.

If the vehicle operator performs downshifting SD once while depressingthe accelerator pedal 32, the shift range is shifted down to the rangewhere more appropriate driving force is obtained. As a result, thevehicle operator does not have to perform the downshifting SD twice ormore for establishing the gear stage in which the required higher enginebraking force is obtained.

Meanwhile, in the automatic transmission including a manual shift modeof a general range hold type, the shift range is changed to the onehaving the highest gear as being one stage higher at every upshiftingSU, or the shift range is changed to the one having the highest gear asbeing one stage lower at every downshifting SD.

In the aforementioned technology, even if the downshifting SD isoperated once during running at the manual shift mode, downshifting tothe gear stage in which the required higher engine braking force oracceleration cannot be established. Accordingly, the downshifting SD hasto be further performed once or twice.

This embodiment makes it possible to reduce the frequency ofdownshifting SD to the gear stage intended by the vehicle operator uponrunning at the manual shift mode.

Fourth Embodiment

A fourth embodiment of the invention will be described referring to FIG.13.

The embodiment is different from the first embodiment in the points asdescribed below.

The uphill/downhill control is performed in the manual shift mode; and

The fourth shift range set control is executed under the uphill/downhillcontrol executed at the manual shift mode.

The elements constituting the structure, which are identical to those inthe first embodiment will be designated with the same referencenumerals, and each explanation of those elements, therefore, will beomitted. The explanation of the aforementioned two different points areexplained hereinafter.

In this embodiment, the T-ECU 15 serves to set the gear stage uponmanual shifting, set the shift range upon manual shifting, and limit thegear stage upon manual shifting.

(Uphill/Downhill Running Control)

The T-ECU 15 executes the uphill/downhill running control in which thehighest gear in the currently set shift range is limited to the one tobe lower than the highest gear in the currently set shift range based onthe slope resistance to the vehicle that runs uphill/downhill at themanual shift mode.

The uphill/downhill running control is a generally employed technology.In this embodiment, the slope resistance resulting from running on theuphill/downhill is detected on the basis of the throttle opening TH andthe vehicle acceleration. The slope resistance resulting from running onthe uphill/downhill constitutes the third vehicle operation information.

More specifically, in the case where the gear stage is set to the 4thspeed in the shift range 5 at the manual shift mode, when the detectionvalue (positive) of the slope resistance resulting from running on theuphill becomes equal to or greater than a predetermined first slopereference value, setting of the gear to the 5th speed is inhibited bylimiting the highest gear to the 4th speed.

In the case where the gear stage is set to the 3rd speed in the shiftrange 4 or 5, when the detection value of the slope resistance resultingfrom running on the uphill becomes equal to or greater than a secondslope reference value that is larger than the first reference value,setting of the gear to the 4th speed is inhibited by limiting thehighest gear to the 3rd speed.

In the case where the gear stage is set to the 2nd speed in one of theshift range 3, 4 and 5, when the detection value of the slope resistanceresulting from running on the uphill becomes equal to or greater than athird slope reference value that is larger than the second referencevalue, setting of the gear to the 3rd speed is inhibited by limiting thehighest gear to the 2nd speed.

In the case where the gear stage is set to the 4th speed in the shiftrange 5 at the manual shift mode, when the detection value (negative) ofthe slope resistance resulting from running on the downhill becomesequal to or greater than a fourth slope reference value, setting of thegear to the 5th speed is inhibited by limiting the highest gear to the4th speed.

In the case where the gear stage is set to the 3rd speed in the shiftrange 4 or 5, when the detection value of the slope resistance resultingfrom running on the downhill becomes equal to or greater than a fifthslope reference value that is larger than the fourth reference value,setting of the gear to the 4th speed is inhibited by limiting thehighest gear to the 3rd speed.

In the case where the gear stage is set to the 2nd speed in one of theshift ranges 3, 4, and 5, when the detection value of the sloperesistance resulting from running on the downhill becomes equal to orgreater than a sixth slope reference value that is larger than the fifthreference value, setting of the gear to the 3rd speed is inhibited bylimiting the highest gear to the 2nd speed.

The T-ECU 15 executes the fourth shift range set control in which theshift range set upon downshifting SD under the uphill/downhill runningcontrol at the manual shift mode is established on the basis of thelimited highest gear stage.

In the embodiment, the highest gear stage limited under theuphill/downhill running control constitutes the fourth vehicle operationinformation. Under the fourth shift range set control, the T-ECU 15 setsthe shift range to the range having the highest gear as being one stagelower than the highest gear limited under the uphill/downhill runningcontrol.

(Fourth Shift Range Set Control)

The routine for the fourth shift range set control will be describedreferring to a flowchart shown in FIG. 13.

First in S400, it is determined whether the shift mode is set to themanual shift mode on the basis of the shift position SP. If NO isobtained in S400, that is, the manual shift mode is not set, the processreturns. If YES is obtained in S400, that is, the manual shift mode isset, the process proceeds to S401 where a gear set inhibition flag XENis cleared.

Then in S402, it is determined whether the shift range 5 is currentlyset, and the upshifting to the 5th speed is inhibited under theuphill/downhill running control such that the 4th gear is set.

If YES is obtained in S402, that is, the upshifting to the 5th speed isinhibited, the process proceeds to S403 where the gear set inhibitionflag XEN is set to 5th, and the process proceeds to S404.

If NO is obtained in S402, that is, upshifting to the 5th speed is notinhibited, the process proceeds to S404. In S404, it is determinedwhether the shift range 5 or 4 is currently set, and the upshifting tothe 4th speed is inhibited under the uphill/downhill running controlsuch that the 3rd speed is set.

If YES is obtained in S404, that is, upshifting to the 4th speed isinhibited, the process proceeds to S405 where the gear set inhibitionflag XEN is set to 4th, and the process proceeds to S406.

If NO is obtained in S404, that is, upshifting to the 4th speed is notinhibited, the process proceeds to S406. In S406, it is determinedwhether one of the shift ranges 5, 4, and 3 is currently set, and theupshifting to the 3rd speed is inhibited under the uphill/downhillrunning control such that the 2nd speed is set.

If YES is obtained in S406, that is, upshifting to the 3rd speed isinhibited, the process proceeds to S407 where the gear set inhibitionflag XEN is set to 3rd, and the process proceeds to S408.

If NO is obtained in S406, that is, upshifting to the 3rd speed is notinhibited, the process proceeds to S408. In S408, it is determinedwhether the downshifting SD has been performed. If NO is obtained inS408, the process returns to S400 from where the control routine isexecuted repeatedly.

If YES is obtained in S408, that is, the downshifting SD has beenperformed, the process proceeds to S409 where the gear that has been setcorresponding to the gear set inhibition flag XEN is determined. If thegear set inhibition flag XEN is set to the 5th speed, the processproceeds to S410 where the currently set shift range 5 is shifted to theshift range 3, and accordingly the gear stage is downshifted from the4th to the 3rd speed.

If the gear set inhibition flag XEN is set to the 4th speed, the processproceeds to S411 where the currently set shift range 5 or 4 is shiftedto the shift range 2, and accordingly the gear stage is shifted from the3rd to the 2nd speed.

If the gear set inhibition flag XEN is set to the 3rd speed, the processproceeds to S412 where the currently set shift range 5, 4, or 3 isshifted to the shift range 2, and accordingly the 2nd speed is held.

(Operation)

Operations of the above-structured embodiment will be described. In thecase where the vehicle is running in the 4th speed in the shift range 5at the manual shift mode, upon running on the gentle uphill, theuphill/downhill running control starts under which upshifting to the 5thspeed is inhibited such that the 4th speed is held.

If the vehicle operator performs the downshifting SD once for the higherforce in the aforementioned case, the shift range 5 is shifted to therange 3, and accordingly the 4th speed is downshifted to the 3rd speed.

Accordingly if the downshifting SD is further performed once forrequiring the higher driving force upon running on the gentle uphill inthe 4th speed in the shift range 5 at the manual shift mode, the gearstage is downshifted from the 4th to the 3rd speed.

In the case where the vehicle is running in the 3rd speed in the shiftrange 5 or 4 at the manual shift mode, upon running on the relativelysteep uphill, the uphill/downhill running control starts under whichupshifting to the 4th speed is inhibited such that the 3rd speed isheld.

If the vehicle operator performs downshifting SD once for requiringhigher driving force in the aforementioned case, the shift range 4 isshifted to the range 2, and accordingly the 3rd speed is downshifted tothe 2nd speed.

Accordingly upon running on the relatively steep uphill in the 3rd speedin the shift range 5 or 4 at the manual shift mode, the gear stage isdownshifted from the 3rd speed to the 2nd speed by a single downshiftingSD for requiring higher driving force.

In the case where the vehicle is running in the 2nd speed in the shiftrange 5, 4, or 3 at the manual shift mode, upon running on the steepuphill, the uphill/downhill running control starts under whichupshifting to the 3rd speed is inhibited such that the 2nd speed isheld.

If the vehicle operator performs downshifting SD once for requiringhigher driving force in the aforementioned case, the shift range 3 isshifted to the range 2, and accordingly the gear stage is held in the2nd speed.

Accordingly upon running on the steep uphill in the 2nd speed in theshift range 5, 4, or 3 at the manual shift mode, the gear stage is notdownshifted to the 1st speed but held in the 2nd speed even if thedownshifting SD is performed once for requiring the higher drivingforce.

If the downshifting SD is performed in the vehicle running state at themanual shift mode where the uphill/downhill running control is notexecuted because of small slope resistance, the currently set shiftrange is shifted down to the range having the highest gear as being onestage lower under the normal manual shift control.

If the downshifting SD is performed so as to prevent upshifting to the5th speed upon acceleration immediately after selecting the shift range5, the manual shift control for downshifting the gear from the currentlyset speed is not executed.

(Effect)

The effects obtained from the aforementioned embodiment will bedescribed.

(5) If the uphill/downhill running control is executed at the manualshift mode so as to inhibit setting of the gear stage as being lowerthan the highest gear in the currently set shift range, a singledownshifting SD (manual shift operation) allows downshifting to the gearstage at which higher driving force is obtained. This makes it possibleto avoid the failure in downshifting to the required gear stage even ifthe downshifting SD is performed for requiring higher engine brakingforce or driving force.

If the uphill/downhill running control is not executed at the manualshift mode, the shift range is shifted down to the range having thehighest gear as being one stage lower than that in the currently setshift range at every performance of downshifting SD. In the case wherethe downshifting SD is performed to inhibit upshifting to the highergear stage by the vehicle operator upon acceleration, downshifting tothe gear is not performed.

In the automatic transmission including the manual shift mode of generalrange hold type, even when the vehicle operator performs downshifting SDfor requiring higher driving force during running at the manual shiftmode under the uphill/downhill running control, downshifting to the gearis not performed. In the case where the shift range having the highestgear that is higher than the inhibited gear is set, the highest gearstage in the range set upon the downshifting SD does not become lowerthan the required gear stage. In the aforementioned case, thedownshifting SD performed once or twice is necessary for downshifting tothe gear in which the required driving force is obtained.

In the shift control apparatus disclosed in JP-A-9-14417, the currentlyset gear is downshifted to the gear as being one stage or two stageslower in response to the downshifting operation. According to thistechnology, however, in the case where the downshifting is performed bythe vehicle operator to inhibit upshifting to the higher gear uponacceleration, the gear is downshifted.

According to the embodiment, downshifting to the gear required by thevehicle operator at the manual shift mode can be performed by reducedfrequency of downshifting SD.

Other Embodiments

Embodiments other than those embodiments 1, 2, 3, and 4 will bedescribed.

(a) In the second embodiment, the T-ECU 15 executes a low-temperaturecontrol that inhibits upshifting to the gear stage in which the requiredengine speed NE is not obtained when the cooling water temperature TW asthe third vehicle operation information is low upon running at theautomatic shift mode as well as the uphill/downhill running control.

The aforementioned low-temperature control is a known technology forlimiting the highest gear to, for example, the 3rd speed withoutupshifting in spite of the vehicle operation state that demandsupshifting from the 3rd to the 4th speed under the automatic shiftcontrol when the water temperature TW is smaller than a predeterminedfirst water temperature reference value. If the water temperature TW issmaller than a second water temperature reference value larger than thefirst water temperature reference value, upshifting from the 4th to the5th speed is not performed so as to limit the highest gear to the 4thspeed. Upon change in the shift mode from the automatic shift mode tothe manual shift mode, the T-ECU 15 serves to set the shift range havingthe highest gear as being the limited gear (second vehicle operationinformation) under the low-temperature control.

Even if the highest gear limited under the low-temperature control atthe automatic shift mode is different, the shift range having thehighest gear corresponding to the limited highest gear is set uponchange in the shift mode to the manual mode. This makes it possible toavoid setting of the gear stage that fails to provide the requiredengine speed sufficient for increasing the water temperature afterchanging the shift mode to the manual shift mode. Accordingly the gearstage in which the required higher driving force or the engine brakingforce is obtained can be established by only a single downshifting atthe manual shift mode.

(b) In the aforementioned embodiment, an ATF temperature control isexecuted such that upshifting from a certain gear stage is inhibitedwhen the temperature of the lubricating oil (ATF) for the automatictransmission as the third vehicle operation information is low as wellas the low-temperature control. In the case where the highest gear islimited at the automatic shift mode under the ATF temperature control,the shift range having the highest gear limited under the ATFtemperature control after changing from the automatic to the manualshift mode is set. In this case, even if the highest gear limited underthe ATF temperature control at the automatic shift mode is differentfrom the highest gear at the manual shift mode, the shift range havingthe highest gear as being limited can be set. As a result, a singledownshifting SD at the manual shift mode makes it possible to establishthe gear in which the higher driving force or the engine braking forcerequired by the vehicle operator is obtained.

(c) In the first embodiment, an engine load resulting from the change inthe shift mode from the automatic mode to the manual mode may be used asthe second vehicle operation information instead of the vehicle speed V,based on which the shift range after changing the shift mode is set. Theengine load may be estimated on the basis of the throttle opening TH andthe engine speed NE, for example. In the aforementioned case under thefirst shift range set control as shown in the flowchart 15A, it isdetermined whether the engine load EGLD is equal to or larger than afirst load reference value EGLD 1. Then in S104, it is determinedwhether the engine load EGLD is equal to or larger than a second loadreference value EGLD2 that is smaller than the first load referencevalue EGLD1. Execution of the aforementioned steps makes it possible toclassify the engine load EGLD into three states, that is, a high loadstate where the 3rd speed is selected at the automatic shift mode uponrunning on the uphill/downhill or towing, a medium load state where the4th speed is selected, and a low load state where the 5th speed isselected. In the high load state, the 3 range flag sftch3RG is set to 1in S103. In the medium load state, the 4 range flag sftch4RG is set to 1in S105. In the low load state, the 5 range flag sftch5RG is set to 1 inS106. In the above-structured embodiment, the similar effects to thosedescribed in (1) to (3) in the first embodiment can be obtained.

In this embodiment, the slope resistance (running resistance) may beused instead of the engine load. The slope resistance may be estimatedfrom the throttle opening TH and the vehicle acceleration derived fromthe vehicle speed V.

(d) In the first embodiment, a speed for depressing the acceleratorpedal or an accelerator operation speed upon change in the shift modefrom the automatic mode to the manual mode may be used as the secondvehicle operation information instead of the vehicle speed V, based onwhich the shift range after changing the shift mode is set. The speedfor depressing the accelerator pedal may be derived from the amount ofchange in the accelerator opening per unit of time. In theaforementioned case under the first shift range set control, as shown inthe flowchart in FIG. 15B, it is determined whether the acceleratoroperation speed ACCF is equal to or greater than a first speed referencevalue ACCF1 in S102. Then in S104, it is determined whether the speedfor depressing the accelerator pedal ACCF is smaller than a second speedreference value ACCF2 that is smaller than the first speed referencevalue ACCF 1. Execution of the aforementioned steps makes it possible toclassify the speed for depressing the accelerator pedal ACCF into threestates, that is, a high speed state required by the vehicle operator forthe highest acceleration torque, a medium speed for the next highestacceleration torque, and a low speed for the higher acceleration torque.In the high speed state, the 3 range flag sftch3RG is set to 1 in S103.In the medium speed state, the 4 range flag sftch4RG is set to 1 inS105. In the low speed state, the 5 range flag sftch5RG is set to 1 inS106. In the above-structured embodiment, the similar effects to thosedescribed in (1) to (3) in the first embodiment can be obtained.

A speed for releasing the accelerator pedal (accelerator pedal operationspeed) may be used as the second vehicle operation information insteadof the speed for depressing the accelerator pedal.

(e) The second embodiment may be structured such that only the secondshift range set control is executed. The third embodiment may bestructured such that only the third shift range set control is executed.The fourth embodiment may be structured such that only the fourth shiftrange set control is executed. The first embodiment may be structuredsuch that the first to the fourth shift range set controls are executed.

(f) According to the first to the fourth embodiments, the T-ECU 15 setsthe gear selected based on the second vehicle operation information uponchange in the shift mode from the automatic to the manual mode, and thenholds the set gear. The T-ECU 15 further sets the gear to be one stagehigher or lower by the downshifting SD or upshifting SU at the manualshift mode. The manual shift mode is set in the shift control apparatusof gear hold type, not of the range hold type as in the first to thefourth embodiments. According to the aforementioned structure, theeffects as described in (1) and (3) of the first embodiment will beobtained.

(g) The fourth embodiment is structured so as to set the shift rangeshifted down to the lower range by the downshifting SD upon running atthe manual shift mode on the basis of the speed for depressing theaccelerator pedal 32 (fourth vehicle operation information).

Referring to the flowchart of FIG. 14, if it is determined that themanual shift mode has been set in S500, the process proceeds to S501where it is determined whether the accelerator pedal depression speedACCF exceeds the first speed reference value ACCF1. Then in S502, it isdetermined whether the ACCF exceeds the second speed reference valueACCF2 that is smaller than the ACCF1. In the aforementioned execution ofsteps S501 and S502, the ACCF is determined as being in one of the threespeed ranges, that is, high-speed, medium-speed, and low-speed ranges,respectively. Then in S503, S504, and S505, the shift range to beselected in accordance with the determined speed range is set,respectively. More specifically, if the ACCF is determined as in thehigh-speed range, the process proceeds to S505 where the shift range isshifted to the three-stage lower than the currently set range. If theACCF is determined as in the medium-speed range, the process proceeds toS504 where the shift range is shifted to the two-stage lower than thecurrently set range. If the ACCF is determined as in the low-speedrange, the process proceeds to S503 where the shift range is shifted tothe one-stage lower than the currently set range. When the downshiftingSD is detected in S506, the shift range is shifted down to the range setin accordance with the ACCF in S507, S508, S509, and S510. If the setshift range becomes lower than the range L, the shift range is set to L.

The embodiment is structured to set the shift range to be shifted downin accordance with the degree of acceleration desired by the vehicleoperator, which is estimated on the basis of the ACCF upon downshiftingSD while depressing the accelerator pedal 32. Therefore downshifting tothe desired gear stage can be established requiring reduced frequency ofthe downshifting SD.

The embodiment may be structured to set the shift range to be shifteddown in accordance with the brake operation force (fourth vehicleoperation information) applied to the brake pedal instead of the ACCF.In this case, the embodiment is structured to set the shift range to beshifted down in accordance with the degree of deceleration required bythe vehicle operator, which is estimated on the basis of the brakeoperation force upon downshifting SD while depressing the brake pedal.

(h) In the first to the fourth embodiments, the downshifting SD andupshifting SU at the manual shift mode may be executed using the shiftdevice. Referring to FIG. 16, the shift device includes a position (+)for upshifting and a position (−) for downshifting both selectivelyoperated from the position M. The upshifting SU is performed bytemporarily selecting the position from M to (+), and downshifting SD isperformed by temporarily selecting the position from M to (−),respectively.

(Other Technical Concepts)

The technical concepts understood from the aforementioned embodimentswill be described hereinafter.

-   (1) In an embodiment of the shift control apparatus for a vehicular    automatic transmission, the second vehicle operation information    includes at least one of a vehicle speed, a running resistance, an    engine load, and an accelerator pedal operating speed. The running    resistance includes a slope resistance upon running on the    uphill/downhill. The accelerator pedal operation speed includes the    speeds for depressing/releasing the accelerator pedal by the vehicle    operator. According to the aforementioned structure, the appropriate    shift range is set upon change in the shift mode to the manual mode    on the basis of the vehicle running state that can be determined    from the vehicle speed, running resistance or the engine load, and    the intention of the vehicle operation that can be estimated from    the accelerator pedal operation speed.-   (2) In an embodiment, the fourth vehicle operation information    includes at least one of an accelerator opening, an engine load, an    engine torque, a vehicle driving force, a vehicle speed, an    accelerator pedal depressing speed, and a brake operating force.    According to the aforementioned structure, the appropriate shift    range is set upon manual shift operation on the basis of the    intention of the vehicle operator for deceleration that can be    estimated from the accelerator opening, accelerator pedal operation    speed, or the brake operation force as well as the vehicle running    state that can be determined from the engine load, engine torque,    vehicle driving force, vehicle speed or the vehicle acceleration.-   (3) In a still further embodiment, the T-ECU 15 serves to set the    gear stage in the shift range having the highest gear stage    corresponding to the one set at the manual shift mode on the basis    of the first vehicle operation information (vehicle speed V). In the    embodiment, the highest gear stage in the shift range is upshifted    to the higher gear by the upshifting SU performed by manual shift    operation, and is downshifted to the lower gear by the downshifting    SD. This makes it possible to provide the effects similar to those    obtained in the third embodiment.-   (4) In the embodiment, the second vehicle operation information    includes at least one of the vehicle speed, running resistance,    engine load (EGLD), and an accelerator pedal operation speed ACCF    (speed for depressing the accelerator pedal). According to the    aforementioned structure, the effects similar to those as described    in the technical concept (1) may be obtained.-   (5) In the aforementioned technology, at the automatic shift mode,    the T-ECU 15 limits the highest gear stage set on the basis of the    first vehicle operation information to be lower stage based on the    third vehicle operation information. The second vehicle operation    information includes the highest gear limited by the T-ECU 15. In    the embodiment, the shift range having the highest gear    corresponding to the limited highest gear is set. This makes it    possible to provide the similar effects as those obtained in the    embodiment.-   (6) The third vehicle operation information includes a slope    resistance to the vehicle that runs uphill/downhill. In the    embodiment, the gear stage is limited to the lower stage based on    the slope resistance. This makes it possible to provide the similar    effects as those obtained in the embodiment.-   (7) The third vehicle operation information includes a temperature    of cooling water for cooling the internal combustion engine, or a    temperature of oil for the automatic transmission. In the    embodiment, the gear stage is limited to the lower stage on the    basis of the cooling water temperature or the oil temperature. This    makes it possible to provide the similar effects as those obtained    in the embodiment.-   (8) The shift control apparatus for a vehicular automatic    transmission includes an automatic shift mode where the gear stage    is set based on the first vehicle operation information for    selecting the gear stage, and a manual shift mode where the gear    stage is set upon manual shifting operations. Selection between the    automatic shift mode and the manual shift mode is manually    performed. In the shift control apparatus, the gear stage upon    selection in the shift mode from the automatic to the manual mode is    set in accordance with the second vehicle operation information that    is different from the first vehicle operation information. The gear    stage to be set upon manual shift operation at the manual shift mode    is established based on the fourth vehicle operation information.    This makes it possible to provide the similar effects as those in    the embodiments.-   (9) The shift control apparatus for a vehicular automatic    transmission includes an automatic shift mode where the gear stage    is set on the basis of the first vehicle operation information for    selecting the gear stage, and a manual shift mode where the shift    range having the gear stage to be set based on the first vehicle    operation information. Selection between the automatic and manual    shift modes is manually performed. In the shift control apparatus,    the shift range upon selection of the shift mode from the automatic    to the manual mode is set on the basis of the second vehicle    operation information that is different from the first vehicle    operation information. In the shift control apparatus, the shift    range upon manual shift operation at the manual shift mode is set    based on the fourth vehicle operation information. This makes it    possible to provide effects as those in the embodiments.-   (10) One of the aforementioned embodiments and technical concepts    includes a first unit for obtaining the first vehicle operation    information including the throttle opening sensor 25 and a vehicle    speed sensor 26, a unit allowing a manual selection of the shift    mode between the manual and automatic mode, that is, the shift    device 12, an automatic shift unit that sets the gear speed for the    automatic transmission based on the first vehicle operation    information at the automatic shift mode, that is, T-ECU 15, a second    unit for obtaining the second vehicle operation information    including the water temperature sensor 23 and the vehicle speed    sensor 26, and a unit for detecting manual shift operation at the    manual shift mode including the upshift switch 13, and the downshift    switch 14.-   (11) One of the aforementioned embodiments and technical concepts    includes a first unit for obtaining the first vehicle operation    information including the throttle opening sensor 25 and the vehicle    speed sensor 26, a unit allowing a manual selection of the shift    mode between the manual and automatic mode, that is, shift device    12, an automatic shift unit that sets the gear speed for the    automatic transmission on the basis of the first vehicle operation    information at the automatic shift mode, that is, T-ECU 15, a fourth    unit for obtaining the fourth vehicle operation information    including the vehicle speed sensor 26 and the accelerator opening    sensor 33, and a unit for detecting manual shift operation at the    manual shift mode including the upshift switch 13 and the downshift    switch 14.

1. A shift control apparatus for a vehicular automatic transmission,comprising a controller that: sets an automatic shift mode in which agear stage is established based on a first vehicle operation informationused for selecting a gear stage of the automatic transmission, and amanual shift mode having a shift range in which the gear stage isestablished by a manual shift operation, the shift mode being manuallyselected between the automatic shift mode and the manual shift mode, andsets the gear stage upon the manual shift operation at the manual shiftmode based on a fourth vehicle operation information, wherein the fourthvehicle operation information includes a current vehicle accelerationand an acceleration after the manual shift operation at which the gearstage set upon shifting of the shift range to have the a highest gearlimited to be at least one stage lower is established.
 2. A shiftcontrol apparatus according to claim 1, further comprising: a firstvehicle operation information detecting unit that detects the firstvehicle operation information; a mode set unit that sets one of theautomatic shift mode and the manual shift mode by the manual shiftoperation; a fourth vehicle operation information detecting unit thatdetects the fourth vehicle operation information; and a manual operationdetecting unit that detects the manual shift operation at the manualshift mode.
 3. A shift control apparatus for a vehicular automatictransmission, comprising a controller that: sets an automatic shift modein which a gear stage is established based on a first vehicle operationinformation used for selecting a gear stage of the automatictransmission, and a manual shift mode in which a shift range having thegear stage established based on the first vehicle operation informationis selected by a manual shift operation, the shift mode being manuallyselected between the automatic shift mode and the manual shift mode, andsets the shift range upon the manual shift operation at the manual shiftmode based on a fourth vehicle operation information, wherein the fourthvehicle operation information includes a current vehicle accelerationand an acceleration after the manual shift operation at which the gearstage set upon shifting of the shift range to have the a highest gearlimited to be at least one stage lower is established.
 4. A shiftcontrol apparatus according to claim 3, further comprising: a firstvehicle operation information detecting unit that detects the firstvehicle operation information; a mode set unit that sets one of theautomatic shift mode and the manual shift mode by the manual shiftoperation; a fourth vehicle operation information detecting unit thatdetects the fourth vehicle operation information; and a manual operationdetecting unit that detects the manual shift operation at the manualshift mode.
 5. A shift control apparatus according to claim 3, whereinthe fourth vehicle operation information comprises at least one of anaccelerator opening, an engine load, an engine torque, a vehicle drivingforce, a vehicle speed, an accelerator pedal depressing speed, and abrake operating force.
 6. A shift control apparatus according to claim3, wherein the manual shift operation is a downshifting operation; andthe fourth vehicle operation information further includes an acceleratoropening caused by the downshifting operation.
 7. A shift controlapparatus according to claim 3, wherein: the controller limits a highestgear stage set by the manual shift operation at the manual shift mode soas to be at least one stage lower than the highest gear in the shiftrange based on a third vehicle operation information, and sets the shiftrange having a highest gear stage that is one stage lower than thelimited highest gear stage set upon the downshifting operation performedby the manual shift operation; and the fourth vehicle operationinformation comprises the highest gear stage limited to be at least onestage lower.
 8. A shift control apparatus according to claim 7, whereinthe third vehicle operation information comprises a slope resistance tothe vehicle that runs one of uphill and downhill; and the controllerlimits the highest gear stage to be at least one stage lower than thehighest gear stage in the shift range based on the slope resistance. 9.A shift control method for a vehicular automatic transmissioncomprising: setting an automatic shift mode in which a gear stage isestablished based on a first vehicle operation information used forselecting a gear stage of the automatic transmission, and a manual shiftmode having a shift range in which the gear stage is established by amanual shift operation, the shift mode being manually selected betweenthe automatic shift mode and the manual shift mode; and setting the gearstage upon the manual shift operation at the manual shift mode based ona fourth vehicle operation information, wherein the fourth vehicleoperation information includes a current vehicle acceleration and anacceleration after the manual shift operation at which the gear stageset upon shifting of the shift range to have the a highest gear limitedto be at least one stage lower is established.
 10. A shift controlmethod for a vehicular automatic transmission comprising: setting anautomatic shift mode in which a gear stage is established based on afirst vehicle operation information used for selecting a gear stage ofthe automatic transmission, and a manual shift mode in which a shiftrange having the gear stage established based on the first vehicleoperation information is selected by a manual shift operation, the shiftmode being manually selected between the automatic shift mode and themanual shift mode; and setting the shift range upon the manual shiftoperation at the manual shift mode based on a fourth vehicle operationinformation, wherein the fourth vehicle operation information includes acurrent vehicle acceleration and an acceleration after the manual shiftoperation at which the gear stage set upon shifting of the shift rangeto have the a highest gear limited to be at least one stage lower isestablished.